/*
   * LP5521 LED chip driver.
   *
   * Copyright (C) 2010 Nokia Corporation
   *
   * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/i2c.h>
  #include <linux/mutex.h>
  #include <linux/gpio.h>
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/ctype.h>
  #include <linux/spinlock.h>
  #include <linux/wait.h>
  #include <linux/leds.h>
  #include <linux/leds-lp5521.h>
  #include <linux/workqueue.h>
  #include <linux/slab.h>
  
  #define LP5521_PROGRAM_LENGTH		32	/* in bytes */
  
  #define LP5521_MAX_LEDS			3	/* Maximum number of LEDs */
  #define LP5521_MAX_ENGINES		3	/* Maximum number of engines */
  
  #define LP5521_ENG_MASK_BASE		0x30	/* 00110000 */
  #define LP5521_ENG_STATUS_MASK		0x07	/* 00000111 */
  
  #define LP5521_CMD_LOAD			0x15	/* 00010101 */
  #define LP5521_CMD_RUN			0x2a	/* 00101010 */
  #define LP5521_CMD_DIRECT		0x3f	/* 00111111 */
  #define LP5521_CMD_DISABLED		0x00	/* 00000000 */
  
  /* Registers */
  #define LP5521_REG_ENABLE		0x00
  #define LP5521_REG_OP_MODE		0x01
  #define LP5521_REG_R_PWM		0x02
  #define LP5521_REG_G_PWM		0x03
  #define LP5521_REG_B_PWM		0x04
  #define LP5521_REG_R_CURRENT		0x05
  #define LP5521_REG_G_CURRENT		0x06
  #define LP5521_REG_B_CURRENT		0x07
  #define LP5521_REG_CONFIG		0x08
  #define LP5521_REG_R_CHANNEL_PC		0x09
  #define LP5521_REG_G_CHANNEL_PC		0x0A
  #define LP5521_REG_B_CHANNEL_PC		0x0B
  #define LP5521_REG_STATUS		0x0C
  #define LP5521_REG_RESET		0x0D
  #define LP5521_REG_GPO			0x0E
  #define LP5521_REG_R_PROG_MEM		0x10
  #define LP5521_REG_G_PROG_MEM		0x30
  #define LP5521_REG_B_PROG_MEM		0x50
  
  #define LP5521_PROG_MEM_BASE		LP5521_REG_R_PROG_MEM
  #define LP5521_PROG_MEM_SIZE		0x20
  
  /* Base register to set LED current */
  #define LP5521_REG_LED_CURRENT_BASE	LP5521_REG_R_CURRENT
  
  /* Base register to set the brightness */
  #define LP5521_REG_LED_PWM_BASE		LP5521_REG_R_PWM
  
  /* Bits in ENABLE register */
  #define LP5521_MASTER_ENABLE		0x40	/* Chip master enable */
  #define LP5521_LOGARITHMIC_PWM		0x80	/* Logarithmic PWM adjustment */
  #define LP5521_EXEC_RUN			0x2A
  
  /* Bits in CONFIG register */
  #define LP5521_PWM_HF			0x40	/* PWM: 0 = 256Hz, 1 = 558Hz */
  #define LP5521_PWRSAVE_EN		0x20	/* 1 = Power save mode */
  #define LP5521_CP_MODE_OFF		0	/* Charge pump (CP) off */
  #define LP5521_CP_MODE_BYPASS		8	/* CP forced to bypass mode */
  #define LP5521_CP_MODE_1X5		0x10	/* CP forced to 1.5x mode */
  #define LP5521_CP_MODE_AUTO		0x18	/* Automatic mode selection */
  #define LP5521_R_TO_BATT		4	/* R out: 0 = CP, 1 = Vbat */
  #define LP5521_CLK_SRC_EXT		0	/* Ext-clk source (CLK_32K) */
  #define LP5521_CLK_INT			1	/* Internal clock */
  #define LP5521_CLK_AUTO			2	/* Automatic clock selection */
  
  /* Status */
  #define LP5521_EXT_CLK_USED		0x08

  /* default R channel current register value */
  #define LP5521_REG_R_CURR_DEFAULT	0xAF

  struct lp5521_engine {

  	int		id;
  	u8		mode;
  	u8		prog_page;
  	u8		engine_mask;
  };
  
  struct lp5521_led {
  	int			id;
  	u8			chan_nr;
  	u8			led_current;
  	u8			max_current;
  	struct led_classdev	cdev;
  	struct work_struct	brightness_work;
  	u8			brightness;
  };
  
  struct lp5521_chip {
  	struct lp5521_platform_data *pdata;
  	struct mutex		lock; /* Serialize control */
  	struct i2c_client	*client;
  	struct lp5521_engine	engines[LP5521_MAX_ENGINES];
  	struct lp5521_led	leds[LP5521_MAX_LEDS];
  	u8			num_channels;
  	u8			num_leds;
  };

  static inline struct lp5521_led *cdev_to_led(struct led_classdev *cdev)
  {
  	return container_of(cdev, struct lp5521_led, cdev);
  }
  
  static inline struct lp5521_chip *engine_to_lp5521(struct lp5521_engine *engine)
  {
  	return container_of(engine, struct lp5521_chip,
  			    engines[engine->id - 1]);
  }
  
  static inline struct lp5521_chip *led_to_lp5521(struct lp5521_led *led)
  {
  	return container_of(led, struct lp5521_chip,
  			    leds[led->id]);
  }

  
  static void lp5521_led_brightness_work(struct work_struct *work);
  
  static inline int lp5521_write(struct i2c_client *client, u8 reg, u8 value)
  {
  	return i2c_smbus_write_byte_data(client, reg, value);
  }
  
  static int lp5521_read(struct i2c_client *client, u8 reg, u8 *buf)
  {
  	s32 ret;
  
  	ret = i2c_smbus_read_byte_data(client, reg);
  	if (ret < 0)
  		return -EIO;
  
  	*buf = ret;
  	return 0;
  }
  
  static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode)
  {
  	struct lp5521_chip *chip = engine_to_lp5521(engine);
  	struct i2c_client *client = chip->client;
  	int ret;
  	u8 engine_state;
  
  	/* Only transition between RUN and DIRECT mode are handled here */
  	if (mode == LP5521_CMD_LOAD)
  		return 0;
  
  	if (mode == LP5521_CMD_DISABLED)
  		mode = LP5521_CMD_DIRECT;
  
  	ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state);

  	if (ret < 0)
  		return ret;

  
  	/* set mode only for this engine */
  	engine_state &= ~(engine->engine_mask);
  	mode &= engine->engine_mask;
  	engine_state |= mode;

  	return lp5521_write(client, LP5521_REG_OP_MODE, engine_state);

  }
  
  static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
  {
  	struct lp5521_chip *chip = engine_to_lp5521(eng);
  	struct i2c_client *client = chip->client;
  	int ret;
  	int addr;
  	u8 mode;
  
  	/* move current engine to direct mode and remember the state */
  	ret = lp5521_set_engine_mode(eng, LP5521_CMD_DIRECT);

  	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
  	usleep_range(1000, 2000);

  	ret |= lp5521_read(client, LP5521_REG_OP_MODE, &mode);
  
  	/* For loading, all the engines to load mode */
  	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);

  	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
  	usleep_range(1000, 2000);

  	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_LOAD);

  	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
  	usleep_range(1000, 2000);

  
  	addr = LP5521_PROG_MEM_BASE + eng->prog_page * LP5521_PROG_MEM_SIZE;
  	i2c_smbus_write_i2c_block_data(client,
  				addr,
  				LP5521_PROG_MEM_SIZE,
  				pattern);
  
  	ret |= lp5521_write(client, LP5521_REG_OP_MODE, mode);
  	return ret;
  }
  
  static int lp5521_set_led_current(struct lp5521_chip *chip, int led, u8 curr)
  {
  	return lp5521_write(chip->client,
  		    LP5521_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
  		    curr);
  }

  static void lp5521_init_engine(struct lp5521_chip *chip)

  {
  	int i;
  	for (i = 0; i < ARRAY_SIZE(chip->engines); i++) {
  		chip->engines[i].id = i + 1;
  		chip->engines[i].engine_mask = LP5521_ENG_MASK_BASE >> (i * 2);
  		chip->engines[i].prog_page = i;

  	}
  }

  static int lp5521_configure(struct i2c_client *client)

  {
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	int ret;

  	lp5521_init_engine(chip);

  	/* Set all PWMs to direct control mode */
  	ret = lp5521_write(client, LP5521_REG_OP_MODE, 0x3F);
  
  	/* Enable auto-powersave, set charge pump to auto, red to battery */
  	ret |= lp5521_write(client, LP5521_REG_CONFIG,
  		LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT);
  
  	/* Initialize all channels PWM to zero -> leds off */
  	ret |= lp5521_write(client, LP5521_REG_R_PWM, 0);
  	ret |= lp5521_write(client, LP5521_REG_G_PWM, 0);
  	ret |= lp5521_write(client, LP5521_REG_B_PWM, 0);
  
  	/* Set engines are set to run state when OP_MODE enables engines */
  	ret |= lp5521_write(client, LP5521_REG_ENABLE,
  			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM |
  			LP5521_EXEC_RUN);

  	/* enable takes 500us. 1 - 2 ms leaves some margin */
  	usleep_range(1000, 2000);

  
  	return ret;
  }
  
  static int lp5521_run_selftest(struct lp5521_chip *chip, char *buf)
  {
  	int ret;
  	u8 status;
  
  	ret = lp5521_read(chip->client, LP5521_REG_STATUS, &status);
  	if (ret < 0)
  		return ret;
  
  	/* Check that ext clock is really in use if requested */
  	if (chip->pdata && chip->pdata->clock_mode == LP5521_CLOCK_EXT)
  		if  ((status & LP5521_EXT_CLK_USED) == 0)
  			return -EIO;
  	return 0;
  }
  
  static void lp5521_set_brightness(struct led_classdev *cdev,
  			     enum led_brightness brightness)
  {
  	struct lp5521_led *led = cdev_to_led(cdev);
  	led->brightness = (u8)brightness;
  	schedule_work(&led->brightness_work);
  }
  
  static void lp5521_led_brightness_work(struct work_struct *work)
  {
  	struct lp5521_led *led = container_of(work,
  					      struct lp5521_led,
  					      brightness_work);
  	struct lp5521_chip *chip = led_to_lp5521(led);
  	struct i2c_client *client = chip->client;
  
  	mutex_lock(&chip->lock);
  	lp5521_write(client, LP5521_REG_LED_PWM_BASE + led->chan_nr,
  		led->brightness);
  	mutex_unlock(&chip->lock);
  }
  
  /* Detect the chip by setting its ENABLE register and reading it back. */
  static int lp5521_detect(struct i2c_client *client)
  {
  	int ret;
  	u8 buf;
  
  	ret = lp5521_write(client, LP5521_REG_ENABLE,
  			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM);
  	if (ret)
  		return ret;

  	/* enable takes 500us. 1 - 2 ms leaves some margin */
  	usleep_range(1000, 2000);

  	ret = lp5521_read(client, LP5521_REG_ENABLE, &buf);
  	if (ret)
  		return ret;
  	if (buf != (LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM))
  		return -ENODEV;
  
  	return 0;
  }
  
  /* Set engine mode and create appropriate sysfs attributes, if required. */
  static int lp5521_set_mode(struct lp5521_engine *engine, u8 mode)
  {

  	int ret = 0;
  
  	/* if in that mode already do nothing, except for run */
  	if (mode == engine->mode && mode != LP5521_CMD_RUN)
  		return 0;
  
  	if (mode == LP5521_CMD_RUN) {
  		ret = lp5521_set_engine_mode(engine, LP5521_CMD_RUN);
  	} else if (mode == LP5521_CMD_LOAD) {
  		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
  		lp5521_set_engine_mode(engine, LP5521_CMD_LOAD);

  	} else if (mode == LP5521_CMD_DISABLED) {
  		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
  	}

  	engine->mode = mode;
  
  	return ret;
  }
  
  static int lp5521_do_store_load(struct lp5521_engine *engine,
  				const char *buf, size_t len)
  {
  	struct lp5521_chip *chip = engine_to_lp5521(engine);
  	struct i2c_client *client = chip->client;
  	int  ret, nrchars, offset = 0, i = 0;
  	char c[3];
  	unsigned cmd;
  	u8 pattern[LP5521_PROGRAM_LENGTH] = {0};
  
  	while ((offset < len - 1) && (i < LP5521_PROGRAM_LENGTH)) {
  		/* separate sscanfs because length is working only for %s */
  		ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);

  		if (ret != 2)
  			goto fail;

  		ret = sscanf(c, "%2x", &cmd);
  		if (ret != 1)
  			goto fail;
  		pattern[i] = (u8)cmd;
  
  		offset += nrchars;
  		i++;
  	}
  
  	/* Each instruction is 16bit long. Check that length is even */
  	if (i % 2)
  		goto fail;
  
  	mutex_lock(&chip->lock);

  	if (engine->mode == LP5521_CMD_LOAD)
  		ret = lp5521_load_program(engine, pattern);
  	else
  		ret = -EINVAL;

  	mutex_unlock(&chip->lock);
  
  	if (ret) {
  		dev_err(&client->dev, "failed loading pattern
  ");
  		return ret;
  	}
  
  	return len;
  fail:
  	dev_err(&client->dev, "wrong pattern format
  ");
  	return -EINVAL;
  }
  
  static ssize_t store_engine_load(struct device *dev,
  				     struct device_attribute *attr,
  				     const char *buf, size_t len, int nr)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	return lp5521_do_store_load(&chip->engines[nr - 1], buf, len);
  }
  
  #define store_load(nr)							\
  static ssize_t store_engine##nr##_load(struct device *dev,		\
  				     struct device_attribute *attr,	\
  				     const char *buf, size_t len)	\
  {									\
  	return store_engine_load(dev, attr, buf, len, nr);		\
  }
  store_load(1)
  store_load(2)
  store_load(3)
  
  static ssize_t show_engine_mode(struct device *dev,
  				struct device_attribute *attr,
  				char *buf, int nr)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	switch (chip->engines[nr - 1].mode) {
  	case LP5521_CMD_RUN:
  		return sprintf(buf, "run
  ");
  	case LP5521_CMD_LOAD:
  		return sprintf(buf, "load
  ");
  	case LP5521_CMD_DISABLED:
  		return sprintf(buf, "disabled
  ");
  	default:
  		return sprintf(buf, "disabled
  ");
  	}
  }
  
  #define show_mode(nr)							\
  static ssize_t show_engine##nr##_mode(struct device *dev,		\
  				    struct device_attribute *attr,	\
  				    char *buf)				\
  {									\
  	return show_engine_mode(dev, attr, buf, nr);			\
  }
  show_mode(1)
  show_mode(2)
  show_mode(3)
  
  static ssize_t store_engine_mode(struct device *dev,
  				 struct device_attribute *attr,
  				 const char *buf, size_t len, int nr)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	struct lp5521_engine *engine = &chip->engines[nr - 1];
  	mutex_lock(&chip->lock);
  
  	if (!strncmp(buf, "run", 3))
  		lp5521_set_mode(engine, LP5521_CMD_RUN);
  	else if (!strncmp(buf, "load", 4))
  		lp5521_set_mode(engine, LP5521_CMD_LOAD);
  	else if (!strncmp(buf, "disabled", 8))
  		lp5521_set_mode(engine, LP5521_CMD_DISABLED);
  
  	mutex_unlock(&chip->lock);
  	return len;
  }
  
  #define store_mode(nr)							\
  static ssize_t store_engine##nr##_mode(struct device *dev,		\
  				     struct device_attribute *attr,	\
  				     const char *buf, size_t len)	\
  {									\
  	return store_engine_mode(dev, attr, buf, len, nr);		\
  }
  store_mode(1)
  store_mode(2)
  store_mode(3)
  
  static ssize_t show_max_current(struct device *dev,
  			    struct device_attribute *attr,
  			    char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lp5521_led *led = cdev_to_led(led_cdev);
  
  	return sprintf(buf, "%d
  ", led->max_current);
  }
  
  static ssize_t show_current(struct device *dev,
  			    struct device_attribute *attr,
  			    char *buf)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lp5521_led *led = cdev_to_led(led_cdev);
  
  	return sprintf(buf, "%d
  ", led->led_current);
  }
  
  static ssize_t store_current(struct device *dev,
  			     struct device_attribute *attr,
  			     const char *buf, size_t len)
  {
  	struct led_classdev *led_cdev = dev_get_drvdata(dev);
  	struct lp5521_led *led = cdev_to_led(led_cdev);
  	struct lp5521_chip *chip = led_to_lp5521(led);
  	ssize_t ret;
  	unsigned long curr;
  
  	if (strict_strtoul(buf, 0, &curr))
  		return -EINVAL;
  
  	if (curr > led->max_current)
  		return -EINVAL;
  
  	mutex_lock(&chip->lock);
  	ret = lp5521_set_led_current(chip, led->id, curr);
  	mutex_unlock(&chip->lock);
  
  	if (ret < 0)
  		return ret;
  
  	led->led_current = (u8)curr;
  
  	return len;
  }
  
  static ssize_t lp5521_selftest(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	int ret;
  
  	mutex_lock(&chip->lock);
  	ret = lp5521_run_selftest(chip, buf);
  	mutex_unlock(&chip->lock);
  	return sprintf(buf, "%s
  ", ret ? "FAIL" : "OK");
  }
  
  /* led class device attributes */

  static DEVICE_ATTR(led_current, S_IRUGO | S_IWUSR, show_current, store_current);

  static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);
  
  static struct attribute *lp5521_led_attributes[] = {
  	&dev_attr_led_current.attr,
  	&dev_attr_max_current.attr,
  	NULL,
  };
  
  static struct attribute_group lp5521_led_attribute_group = {
  	.attrs = lp5521_led_attributes
  };
  
  /* device attributes */

  static DEVICE_ATTR(engine1_mode, S_IRUGO | S_IWUSR,

  		   show_engine1_mode, store_engine1_mode);

  static DEVICE_ATTR(engine2_mode, S_IRUGO | S_IWUSR,

  		   show_engine2_mode, store_engine2_mode);

  static DEVICE_ATTR(engine3_mode, S_IRUGO | S_IWUSR,

  		   show_engine3_mode, store_engine3_mode);

  static DEVICE_ATTR(engine1_load, S_IWUSR, NULL, store_engine1_load);
  static DEVICE_ATTR(engine2_load, S_IWUSR, NULL, store_engine2_load);
  static DEVICE_ATTR(engine3_load, S_IWUSR, NULL, store_engine3_load);

  static DEVICE_ATTR(selftest, S_IRUGO, lp5521_selftest, NULL);
  
  static struct attribute *lp5521_attributes[] = {
  	&dev_attr_engine1_mode.attr,
  	&dev_attr_engine2_mode.attr,
  	&dev_attr_engine3_mode.attr,
  	&dev_attr_selftest.attr,

  	&dev_attr_engine1_load.attr,

  	&dev_attr_engine2_load.attr,

  	&dev_attr_engine3_load.attr,
  	NULL
  };
  
  static const struct attribute_group lp5521_group = {
  	.attrs = lp5521_attributes,
  };

  static int lp5521_register_sysfs(struct i2c_client *client)
  {
  	struct device *dev = &client->dev;
  	return sysfs_create_group(&dev->kobj, &lp5521_group);
  }
  
  static void lp5521_unregister_sysfs(struct i2c_client *client)
  {
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	struct device *dev = &client->dev;
  	int i;
  
  	sysfs_remove_group(&dev->kobj, &lp5521_group);

  	for (i = 0; i < chip->num_leds; i++)
  		sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
  				&lp5521_led_attribute_group);
  }

  static int __devinit lp5521_init_led(struct lp5521_led *led,

  				struct i2c_client *client,
  				int chan, struct lp5521_platform_data *pdata)
  {
  	struct device *dev = &client->dev;
  	char name[32];
  	int res;
  
  	if (chan >= LP5521_MAX_LEDS)
  		return -EINVAL;
  
  	if (pdata->led_config[chan].led_current == 0)
  		return 0;
  
  	led->led_current = pdata->led_config[chan].led_current;
  	led->max_current = pdata->led_config[chan].max_current;
  	led->chan_nr = pdata->led_config[chan].chan_nr;
  
  	if (led->chan_nr >= LP5521_MAX_LEDS) {
  		dev_err(dev, "Use channel numbers between 0 and %d
  ",
  			LP5521_MAX_LEDS - 1);
  		return -EINVAL;
  	}

  	snprintf(name, sizeof(name), "%s:channel%d",
  			pdata->label ?: client->name, chan);

  	led->cdev.brightness_set = lp5521_set_brightness;
  	led->cdev.name = name;
  	res = led_classdev_register(dev, &led->cdev);
  	if (res < 0) {
  		dev_err(dev, "couldn't register led on channel %d
  ", chan);
  		return res;
  	}
  
  	res = sysfs_create_group(&led->cdev.dev->kobj,
  			&lp5521_led_attribute_group);
  	if (res < 0) {
  		dev_err(dev, "couldn't register current attribute
  ");
  		led_classdev_unregister(&led->cdev);
  		return res;
  	}
  	return 0;
  }

  static int __devinit lp5521_probe(struct i2c_client *client,

  			const struct i2c_device_id *id)
  {
  	struct lp5521_chip		*chip;
  	struct lp5521_platform_data	*pdata;
  	int ret, i, led;

  	u8 buf;

  
  	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
  	if (!chip)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, chip);
  	chip->client = client;
  
  	pdata = client->dev.platform_data;
  
  	if (!pdata) {
  		dev_err(&client->dev, "no platform data
  ");
  		ret = -EINVAL;
  		goto fail1;
  	}
  
  	mutex_init(&chip->lock);
  
  	chip->pdata   = pdata;
  
  	if (pdata->setup_resources) {
  		ret = pdata->setup_resources();
  		if (ret < 0)
  			goto fail1;
  	}
  
  	if (pdata->enable) {
  		pdata->enable(0);

  		usleep_range(1000, 2000); /* Keep enable down at least 1ms */

  		pdata->enable(1);

  		usleep_range(1000, 2000); /* 500us abs min. */

  	}

  	lp5521_write(client, LP5521_REG_RESET, 0xff);
  	usleep_range(10000, 20000); /*
  				     * Exact value is not available. 10 - 20ms
  				     * appears to be enough for reset.
  				     */

  
  	/*
  	 * Make sure that the chip is reset by reading back the r channel
  	 * current reg. This is dummy read is required on some platforms -
  	 * otherwise further access to the R G B channels in the
  	 * LP5521_REG_ENABLE register will not have any effect - strange!
  	 */
  	lp5521_read(client, LP5521_REG_R_CURRENT, &buf);
  	if (buf != LP5521_REG_R_CURR_DEFAULT) {
  		dev_err(&client->dev, "error in reseting chip
  ");
  		goto fail2;
  	}
  	usleep_range(10000, 20000);

  	ret = lp5521_detect(client);
  
  	if (ret) {
  		dev_err(&client->dev, "Chip not found
  ");
  		goto fail2;
  	}
  
  	dev_info(&client->dev, "%s programmable led chip found
  ", id->name);

  	ret = lp5521_configure(client);

  	if (ret < 0) {
  		dev_err(&client->dev, "error configuring chip
  ");
  		goto fail2;
  	}
  
  	/* Initialize leds */
  	chip->num_channels = pdata->num_channels;
  	chip->num_leds = 0;
  	led = 0;
  	for (i = 0; i < pdata->num_channels; i++) {
  		/* Do not initialize channels that are not connected */
  		if (pdata->led_config[i].led_current == 0)
  			continue;
  
  		ret = lp5521_init_led(&chip->leds[led], client, i, pdata);
  		if (ret) {
  			dev_err(&client->dev, "error initializing leds
  ");
  			goto fail3;
  		}
  		chip->num_leds++;
  
  		chip->leds[led].id = led;
  		/* Set initial LED current */
  		lp5521_set_led_current(chip, led,
  				chip->leds[led].led_current);
  
  		INIT_WORK(&(chip->leds[led].brightness_work),
  			lp5521_led_brightness_work);
  
  		led++;
  	}
  
  	ret = lp5521_register_sysfs(client);
  	if (ret) {
  		dev_err(&client->dev, "registering sysfs failed
  ");
  		goto fail3;
  	}
  	return ret;
  fail3:
  	for (i = 0; i < chip->num_leds; i++) {
  		led_classdev_unregister(&chip->leds[i].cdev);
  		cancel_work_sync(&chip->leds[i].brightness_work);
  	}
  fail2:
  	if (pdata->enable)
  		pdata->enable(0);
  	if (pdata->release_resources)
  		pdata->release_resources();
  fail1:
  	kfree(chip);
  	return ret;
  }

  static int __devexit lp5521_remove(struct i2c_client *client)

  {
  	struct lp5521_chip *chip = i2c_get_clientdata(client);
  	int i;
  
  	lp5521_unregister_sysfs(client);
  
  	for (i = 0; i < chip->num_leds; i++) {
  		led_classdev_unregister(&chip->leds[i].cdev);
  		cancel_work_sync(&chip->leds[i].brightness_work);
  	}
  
  	if (chip->pdata->enable)
  		chip->pdata->enable(0);
  	if (chip->pdata->release_resources)
  		chip->pdata->release_resources();
  	kfree(chip);
  	return 0;
  }
  
  static const struct i2c_device_id lp5521_id[] = {
  	{ "lp5521", 0 }, /* Three channel chip */
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lp5521_id);
  
  static struct i2c_driver lp5521_driver = {
  	.driver = {
  		.name	= "lp5521",
  	},
  	.probe		= lp5521_probe,

  	.remove		= __devexit_p(lp5521_remove),

  	.id_table	= lp5521_id,
  };

  module_i2c_driver(lp5521_driver);

  
  MODULE_AUTHOR("Mathias Nyman, Yuri Zaporozhets, Samu Onkalo");
  MODULE_DESCRIPTION("LP5521 LED engine");
  MODULE_LICENSE("GPL v2");